Repairing plastic surface or sheet materials using adhesive tapes, patches and coatings are well known in the art. However, such known adhesive tapes etc. are often unsuitable for underwater application, and typically do not have sufficient resistence to an aqueous environment to provide adhesion for extended periods of time. Furthermore, when applying such adhesive tapes etc. to the region or site of repair it is often necessary to evacuate the aqueous environment until the repair process has been completed. This is both time consuming and wasteful.
There is currently a known adhesive tape which is made from a thin (about 1/1000 th of an inch thick) polyvinylfluoride film having the trade name, TEDLAR.TM. (a product of Du Pont). The tape has an adhesive composition on one side made from a resin-plasticizer modified acrylonitrile-butadiene co-polymer. The adhesive composition used on this tape is a low tack, toluene-based, adhesive, having a slow drying time. This makes it less desirable for underwater application. The adhesive composition used is also extremely toxic and discolors or yellows with time, making it aesthetically displeasing. As with all adhesive tapes, the size of the patch is limited to the size of the tape. This places a limitation on repairs of different dimensions.
It has been found that an adhesive composition according to the present invention comprising a resin and plasticizer modified acrylonitrile-butadiene co-polymer, in liquid form, when applied to a patch material and allowed to dry in air for approximately 5-8 minutes prior to being pressed onto the site of repair, provides a superior means of repairing plastic sheet materials, particularly in an aqueous or underwater environment. Such an adhesive may also be applied directly to the surface of the plastic sheet material, at the repair region or site, as a coating.
It is therefore an object of the present invention to provide an adhesive or coating composition, hereinafter referred to as "an adhesive composition", which overcomes one or more of the above-mentioned shortcomings of known adhesives and which provides a more aggressive and/or longer lasting adherence of a material patch compared to the known adhesive tape and/or provides an adhesive which is especially suited for underwater application. It is also an object of the present invention to provide an adhesive composition, in liquid form, which can be applied to a variety of material patches, for compatibly repairing various plastic sheet materials in an aqueous environment.